U.S. patent number 8,900,027 [Application Number 13/475,749] was granted by the patent office on 2014-12-02 for planar plasma lamp and method of manufacture.
This patent grant is currently assigned to Eden Park Illumination, Inc.. The grantee listed for this patent is Jeffry M Bulson, David Blair DeHaven, Cyrus M Herring, Walter E Mason, Sung-Jin Park, Jay E Pogemiller. Invention is credited to Jeffry M Bulson, David Blair DeHaven, Cyrus M Herring, Walter E Mason, Sung-Jin Park, Jay E Pogemiller.
United States Patent |
8,900,027 |
Bulson , et al. |
December 2, 2014 |
Planar plasma lamp and method of manufacture
Abstract
A lamp including a first and second lamp substrate with a first
and second external electrode, respectively, and a first and second
internal phosphor coating, respectively, wherein the first phosphor
coating is a phosphor monolayer. A method of manufacturing a lamp,
including screen-printing a phosphor monolayer on a first lamp
substrate; screen-printing a phosphor layer on a second lamp
substrate; joining the phosphor-coated faces of the first and
second lamp substrates together with a seal; and joining a first
and second electrode to the uncoupled exterior faces of the first
and second lamp substrates, respectively.
Inventors: |
Bulson; Jeffry M (Hopewell
Junction, NY), Pogemiller; Jay E (New Paltz, NY),
DeHaven; David Blair (Urbana, IL), Mason; Walter E
(Alfred, NY), Herring; Cyrus M (Urbana, IL), Park;
Sung-Jin (Champaign, IL) |
Applicant: |
Name |
City |
State |
Country |
Type |
Bulson; Jeffry M
Pogemiller; Jay E
DeHaven; David Blair
Mason; Walter E
Herring; Cyrus M
Park; Sung-Jin |
Hopewell Junction
New Paltz
Urbana
Alfred
Urbana
Champaign |
NY
NY
IL
NY
IL
IL |
US
US
US
US
US
US |
|
|
Assignee: |
Eden Park Illumination, Inc.
(Champaign, IL)
|
Family
ID: |
47177367 |
Appl.
No.: |
13/475,749 |
Filed: |
May 18, 2012 |
Prior Publication Data
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Document
Identifier |
Publication Date |
|
US 20120319559 A1 |
Dec 20, 2012 |
|
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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61487617 |
May 18, 2011 |
|
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Current U.S.
Class: |
445/46; 445/29;
313/574; 445/35; 445/52; 445/33; 445/26; 313/166; 313/607;
313/291 |
Current CPC
Class: |
H01J
9/22 (20130101); H01J 61/305 (20130101); H01J
61/48 (20130101); H01J 9/02 (20130101); H01J
9/266 (20130101); H01J 9/14 (20130101); H01J
9/248 (20130101); H01J 2261/385 (20130101) |
Current International
Class: |
H01J
9/00 (20060101) |
Field of
Search: |
;313/422,493,634,607,484,485,514,515,519,633,631,491,483,475,473,166,291,574 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Patel; Nimeshkumar
Assistant Examiner: Diaz; Jose M
Attorney, Agent or Firm: Schox; Jeffrey Lin; Diana
Parent Case Text
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application
No. 61/487,617, filed 18 May 2011, which is incorporated in its
entirety by this reference.
Claims
We claim:
1. A method of manufacturing a plasma lamp, comprising: screen
printing a first phosphor layer on a broad face of a first planar
lamp substrate; screen printing a second phosphor layer on a second
broad face of a second planar lamp substrate; sealing the
perimeters of the first and second broad faces together, wherein
the first and second broad faces are positioned a separation
distance apart; fabricating a first and second electrode,
comprising: screen-printing a first and second buss electrode along
the perimeter of a broad face of a first and second electrode
substrate, the electrode substrates each comprising a glass plate
coated on a broad face with a transparent conductive film
comprising transparent conductive oxide, wherein screen-printing
the first and second buss electrodes comprises: removing the
transparent conductive oxide from perimeters of the glass plates;
and screen-printing the first and second buss electrodes over the
respective transparent film along the transparent film perimeter;
joining the first electrode to a third broad face after fabricating
the first electrode, the third broad face comprising an uncoupled
broad face of the first substrate; and joining the second electrode
to a fourth broad face after fabricating the second electrode, the
fourth broad face comprising an uncoupled broad face of the second
substrate.
2. The method of claim 1, wherein the first phosphor layer is a
phosphor monolayer, the monolayer having a thickness approximately
equivalent to the largest dimension of a phosphor grain.
3. The method of claim 2, wherein the second phosphor layer
comprises a thickness that facilitates approximately ninety percent
of produced light to be emitted from the first plate and
approximately ten percent of the produced light to be emitted from
the second plate.
4. The method of claim 1, wherein the method further comprises
depositing spherical spacers into the second phosphor layer, the
spherical spacers having a diameter substantially equivalent to the
separation distance between the first and second substrates.
5. The method of claim 1, wherein the second plate further
comprises an opening through the thickness of the second plate.
6. The method of claim 5, wherein sealing the perimeters of the
first and second broad faces comprises: applying frit paste to an
edge of a hollow tube, the tube edge defining substantially the
same geometry as the opening; aligning the tube coaxially with the
opening, the tube edge proximal the fourth broad face; and coupling
the tube to the fourth broad face; wherein sealing the perimeters
of the first and second broad faces concurrently joins the tube
with the second plate.
7. The method of claim 6, wherein the method further comprises
heating a tube end distal from the fourth broad face to collapse
the tube and seal the opening.
8. The method of claim 5, further comprising: baking the first and
second substrates with a lowered pressure in the internal chamber
after sealing together the first and second broad faces, wherein
the low pressure is generated through the opening; and filling the
internal chamber with a working gas through the opening.
9. The method of claim 1, wherein joining the first electrode to
the third broad face comprises laminating the first electrode
against the third broad face; and joining the second film to the
fourth broad face comprises laminating the second electrode against
the fourth broad face.
10. The method of claim 1, wherein the first and second substrates
comprise soda-lime float glass, wherein the method further
comprises strengthening the first and second substrates.
11. The method of claim 10, wherein strengthening the first and
second substrates comprises chemically strengthening the glass.
Description
TECHNICAL FIELD
This invention relates generally to the planar emissive device
field, and more specifically to a new and useful plasma lamp and
method of manufacture in the planar emissive device field.
BACKGROUND
Flat fluorescent lamps are planar "light bulbs" that produce light
over their entire surface area. Many operate as dielectric barrier
discharge lamps, which are constructed of two sheets of glass with
external or dielectric-encapsulated internal planar electrodes that
are used to produce a plasma discharge. The plasma is energized by
a high voltage applied to the electrodes, which produces a
breakdown in the gas. The gas breakdown products cause
luminescence, usually in a phosphor, such that the lamp produces
light.
Conventional flat fluorescent lamp designs rely on complex
geometries and structures that require expensive and complex
fabrication processes, such as those used for plasma display panel
(PDP) production. These processes may include the use of thick film
dielectric paste screening and firing, MgO thin film deposition,
and photolithography-patterned metal electrodes. The complex
construction and expensive manufacturing processes used to make
these conventional lamps drive up the costs of the lamp. To be
competitive with the ubiquitous light bulb, there is a great need
in the planar plasma lamp field to create a new and useful plasma
lamp and method of manufacture that reduces lamp costs.
BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 is a schematic representation of a lamp of the preferred
embodiments.
FIG. 2 is a schematic representation of a distribution of spacers
within the lamp.
FIG. 3 is a schematic representation of an electrode.
FIG. 4 is a flow diagram of a method of manufacturing a lamp.
FIGS. 5A and 5B are schematic representations of applying a first
and second phosphor layer to a first and second lamp substrate,
respectively.
FIG. 6 is a schematic representation of joining the substrates
together.
FIG. 7 is a schematic representation of applying the electrodes to
the substrate exteriors.
FIG. 8 is a schematic representation of fabricating an
electrode.
FIG. 9 is a schematic representation of joining a first and second
protective substrate to the first and second electrodes.
FIG. 10 is a schematic representation of providing an opening
through the thickness of a lamp substrate.
FIG. 11 is a schematic representation of a variation of providing
an opening.
FIG. 12 is a schematic representation of evacuating the internal
chamber and filling the internal chamber with a working gas.
FIG. 13 is a schematic representation of a variation of sealing the
opening.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following description of the preferred embodiments of the
invention is not intended to limit the invention to these preferred
embodiments, but rather to enable any person skilled in the art to
make and use this invention.
1. System.
As shown in FIG. 1, the lamp 100 includes a first and second lamp
substrate 200 with a pair of external electrodes 300; a first and
second phosphor coating 400 on the interior surfaces of the first
and second planar lamp substrates 200, respectively, wherein the
first and second phosphor coatings 400 have different thicknesses;
and a working gas hermetically sealed between the first and second
lamp substrates 200. In one variation of the lamp 100, the first
phosphor coating 400 is a phosphor monolayer, and the thickness of
the second phosphor coating 400 is tailored to optimize luminous
flux. In another variation of the lamp 100, the electrodes 300 are
blanket films of transparent conductive oxide. This lamp 100 is
preferably utilized with a power source to produce visible light
over the active area (e.g. the most of the broad face) of the lamp
100. The lamp 100 can be utilized as a light source, as back
lighting for a display, or for any other suitable light-emitting
purpose.
The construction and manufacture of this lamp 100 can impart
several benefits. First, the lamp 100 can yield light output of
high quality: the light can be bright, dimmable, of uniform
luminance across the surface, have uniform color quality at various
emission angles and intensity levels, have a high color rendering
index (CRI), have a wide range of available chromaticity, and have
good luminous efficacy. Second, the lamp 100 can have a lower
manufacturing cost due to a reduced number of parts requiring fewer
and less complex manufacturing equipment, and/or a reduced number
of manufacturing steps. For example, the lamp substrate 200
functions as the dielectric of the lamp 100, reducing or
eliminating the need for an additional dielectric component. As
another example, the phosphor coatings 400 can be screen printed,
reducing the manufacturing cost through step and equipment
reduction. Furthermore, in one variation of the lamp 100, the
transparent conductive oxide (TCO) or transparent conductive film
can be used as the electrodes 300. Not only does using TCO allow
for the buss electrode 340 to be screen-printed without subsequent
photolithography processes, but using TCO also reduces the material
cost of the lamp 100.
The lamp 100 is preferably utilized with a bipolar-pulsed voltage
source using a MOS-FET H-bridge switching topology. A programmable
microcontroller produces timing signals to trigger drivers for the
MOS-FETs. In one variation, the rail voltage is produced by a power
factor correction (PFC) circuit, which converts a universal AC
input voltage to about 370 VDC. Dimming can be accomplished by
adjusting the pulse repetition frequency (PRF) through 0-10 VDC
input to the microcontroller. However, any other suitable voltage
source and control circuitry can be used.
The first and second lamp substrates 200 of the lamp 100 support
the electrodes 300 and phosphor layers 400, and can additionally
function as the dielectric for the lamp 100. The lamp substrates
200 are preferably substantially similar, and preferably have the
same dimensions, material, treatments, and dielectric constants.
Alternatively, the first and second lamp substrates 200 can have
differing parameters. The lamp substrates 200 are preferably planar
and prismatic, with two opposing broad faces. The lamp substrates
200 are preferably plates (e.g. rectangular prisms), but can
alternatively be curved (e.g. with complimentary curvatures) or
have any other suitable geometry. The lamp substrates 200 are
preferably glass, more preferably chemically strengthened glass. In
one variation, the lamp substrates 200 are made of soda-lime float
glass that has been chemically strengthened by sodium ion-potassium
ion exchange. However, the lamp substrates 200 can be made of
soda-lime container glass, borosilicate glass, any suitable sheet
glass, a polymer, or any other suitable material. The lamp
substrates 200 can be unstrengthened or strengthened, wherein
strengthening can include chemical strengthening, such as ion
exchange, lamination, annealing, or any other suitable
strengthening method.
The first and second lamp substrates 200 are preferably
hermetically sealed together, and cooperatively define an internal
chamber 102. The first and second lamp substrates are preferably
sealed together by glass frit 210, but can alternatively be sealed
in any suitable manner. The distance between the first and second
lamp substrates 200 is preferably substantially uniform, and is
preferably maintained by spacers 220. This distance is
approximately 1.1 mm, but can alternatively be larger or smaller.
The distance is preferably maintained by spherical spacers, wherein
the spacers 220 preferably have a diameter substantially similar to
the desired separation distance (e.g. 1.1 mm, 0.5 mm, etc.).
However, rectangular prismatic, cylindrical, or any other suitable
spacer can be used. Alternatively, the spacing may be accomplished
by molding the back glass substrate with pre-formed spacers (e.g.
bumps) that maintain the spacing between the front and back glass.
The spacers 220 are preferably glass, more preferably the same
glass as the lamp substrates 200, but can be any suitable material.
The spacers 220 are preferably evenly distributed over the active
area of the lamp 100 (e.g. across the broad face of the first and
second lamp substrates 200), but can alternatively be confined to
the lamp/lamp substrate perimeter. As shown in FIG. 2, the spacers
220 are preferably distributed in a grid pattern, but can
alternatively be distributed in any other suitable pattern. In one
variation, the spacers 220 are placed approximately 0.5 inches-1.5
inches (12.7 mm-38.1 mm) apart. The spacer positions are preferably
retained by one of the internal phosphor coatings 400, but can
alternatively be retained by glass frit, friction between the
spacer and the lamp substrate 200, or by any other suitable
mechanism. The lamp substrates 200 are preferably joined by a glass
frit 210 about the lamp substrate perimeters, but can be otherwise
hermetically sealed.
As shown in FIG. 1, the electrodes 300 of the lamp 100 allow a high
voltage to be generated across the lamp thickness to induce a
discharge within the lamp 100. The electrodes 300 are preferably
external electrodes 300, located on the exterior of the lamp
substrates 200, but can alternatively be internal electrodes 300,
wherein the electrodes 300 can additionally include dielectric
elements. The electrodes are preferably planar electrodes, but can
alternatively have any suitable form. Each electrode 300 is
preferably directly joined to the lamp substrate 200, but can
alternatively be joined by an intermediary film, adherent, or
joining medium. As shown in FIG. 3, the electrodes 300 preferably
include a discharge electrode 320 supported by an electrode
substrate 360, located distal the broad faces of the first and
second lamp substrates 200, such that the discharge electrodes 320
are located between the lamp substrate 200 and the electrode
substrate 360. The electrode substrate 360 is preferably a glass
plate, but can alternatively be a polymeric plate, a polymeric film
(e.g. PET film), or any other substrate that can function as an
electrode substrate 360. The electrode substrate 360 preferably has
a broad face substantially the same size and/or geometry as the
broad face of the lamp substrates 200, but can alternatively be
larger or smaller. Each discharge electrode 320 is preferably a
blanket film, but can alternatively be a patterned electrode 300.
The discharge electrodes 320 preferably include transparent
conductive films (TCF). The discharge electrodes 320 are preferably
inorganic films made of transparent conductive oxide (TCO), such as
indium tin oxide (ITO), fluorine-doped tin oxide (FTO), doped zinc
oxide, or any other suitable transparent conductive oxide.
Alternatively, the electrodes 300 can be made of organic films
(e.g. carbon nanotubes, graphine, etc.), transparent conducting
polymers (e.g. poly(3,4-ethylenedioxythiophene) [PEDOT], doped
PEDOT, poly(4,4-dioctylcyclopentadithiophene), derivatives of
polyacetylene, polyaniline, polypyrrole or polythiophene, etc.), or
any other suitable transparent conductive film. Alternatively, the
discharge electrodes 320 can be patterned metal (e.g. copper, gold,
etc.) on a polymer film (e.g. PET film), patterned copper on a
glass substrate, a blanket opaque conductor on a polymer film or
glass substrate (e.g. in a one-sided lamp), or any other suitable
electrode 300. The electrodes 300 are preferably substantially
similar, but can alternatively be different (e.g. the first
electrode 300 can be a TCO coated glass plate and the second
electrode 300 can be a patterned copper PET film). When the
electrode substrate 360 is a film, the electrodes 300 preferably
additionally include a protective substrate 380 as shown in FIG. 9,
coupled to the exterior of the electrode 300 that protects the
electrode film. The broad face of the protective substrate 380
preferably has substantially the same geometry as the broad face of
the lamp substrate 200 and/or the electrode substrate 360, but can
alternatively be larger or smaller. The protective substrate 380 is
preferably a glass plate, but can alternatively be a polymeric
plate. The lamp 100 preferably includes a first and a second
electrode 300 coupled to the first and second substrates,
respectively, but can include three, four, or any other suitable
number of electrodes.
As shown in FIG. 3, the electrodes 300 each preferably additionally
include a buss electrode 340, wherein the buss electrode 340 can
reduce the effective resistance of the electrode 300. The buss
electrode 340 is preferably disposed about the perimeter of the
electrode 300, and is preferably disposed between the lamp
substrate 200 and the electrode 300. The buss electrode preferably
traces the perimeter of the discharge electrode 320, and does not
contact the electrode substrate 380, but can alternatively contact
both the discharge electrode 320 and the electrode substrate 380.
The buss electrode 340 is preferably silver, but can alternatively
be gold, lead, copper, tin, or any other suitable conductive
material. The buss electrode layer is preferably approximately
15-40 microns thick, but can alternatively have any suitable
thickness. The buss electrode 340 can additionally include
terminals 342 (e.g. tin-plated copper terminals, tin terminals,
copper terminals, gold terminals, etc.) that extend from the buss
terminal to the exterior of the lamp 100 (e.g. extends over the
uncovered perimeter of the lamp substrate). The terminals of the
first and second lamp substrates 342 can additionally be
electrically connected to connectors (e.g. wires, plugs, etc.) that
enable connection to the terminals of a power source.
As shown in FIG. 1, the phosphor coatings 400 of the lamp 100
function to emit light when excited by products of the plasma
generated from the discharge. The phosphor coatings 400 are
preferably located on the interior surfaces of the first and second
lamp substrates 200. The first lamp substrate 202 preferably
includes a first phosphor coating 400, and the second lamp
substrate 204 preferably includes a second phosphor coating 400. In
one variation, the first phosphor coating 400 is preferably a
phosphor monolayer, wherein the thickness of the first phosphor
coating 400 is preferably substantially equivalent to the
characteristic dimension (e.g. largest dimension) of a phosphor
grain. The first phosphor coating 400 is preferably less than 25
microns thick; in one variation, the first phosphor coating 400 is
approximately 6-8 microns thick. However, the first phosphor
coating 400 can have any suitable thickness. The second phosphor
coating 400 preferably has a thickness that optimizes luminous flux
for a particular application. In one variation, the thickness of
the second phosphor coating 400 is determined as a multiple of the
thickness of the first phosphor coating 400. For example, the
thickness of the second phosphor coating 400 can be selected such
that ninety percent of light is transmitted through/emitted from
the first lamp substrate 202, while ten percent of light is
transmitted through/emitted from the second substrate 204. In one
variation, the thickness of the second phosphor coating 400 is
approximately 40 microns thick. Alternatively, the first and second
phosphor layers 400 can have the same thickness or any suitable
thickness. The phosphor layers 400 preferably cover substantially
the entire broad face of the respective lamp substrates 200, but
can alternatively cover only a portion of the broad faces. The
phosphor coatings 400 preferably include phosphor grain sizes of
approximately 6-8 microns, but can alternatively include phosphor
grain sizes of approximately 10 microns, between 1-2 microns to 35
microns, or include phosphor grains of any other suitable size. The
phosphor layers 400 can include a single phosphor or a mix of
phosphors selected to produce a given emission spectrum for a given
application. For example, to produce a color gamut substantially
equivalent to a plasma TV, PDP phosphors can be used. For lighting
applications, a mixture of phosphors can be chosen to produce white
light. The chromaticity for this white light can be chosen with the
proper mix of phosphors to achieve the associated correlated color
temperature (CCT). Phosphors that can be used include oxides,
nitrides and oxynitrides, sulfides, selenides, halides or silicates
of zinc, cadmium, manganese, aluminium, silicon, various rare earth
metals, or any other suitable phosphor. The first and second
phosphor coatings 400 preferably have the same composition of
individual phosphor material, but can alternatively have different
compositions. However, any other suitable phosphor composition
compatible with the working gas can be utilized.
The working gas of the lamp 100 functions to form plasma in
response to the high voltage generated between the electrodes 300.
The working gas is preferably hermetically sealed in the internal
volume defined between the first and second lamp substrates 200.
The working gas is preferably a noble gas or a noble gas mixture
and can include other materials, such as metal halides, sodium,
mercury, or sulfur. In one variation of the lamp, the working gas
includes only noble gas, and does not include metal halides,
mercury, or sulfur. In another variation of the lamp, the working
gas includes neon (Ne) and xenon (Xe), wherein the working gas
composition includes 50-100% neon gas and 50-100% xenon gas at a
pressure of 100-600 torr. However, the working gas can
additionally/alternatively include helium (He), argon (Ar), or
krypton (Kr), and can have any other suitable composition.
2. Method of Manufacturing.
As shown in FIG. 4, the method of manufacturing a plasma lamp
includes applying a first and second phosphor layer to a broad face
of a first and second lamp substrate, respectively S100; joining
the first and second lamp substrates together along the perimeter
with the phosphor-coated faces on the interior, wherein the first
and second lamp substrates are separated by a gap distance S300;
and applying electrodes to the exteriors of the first and second
lamp substrates S500. In one variation of the method, the first and
second phosphor layers are screen-printed onto the lamp substrates.
In another variation of the method, the electrode buss is also
screen-printed. By screen-printing one or more of the components,
this method can reduce the cost of manufacturing. The method
preferably produces a lamp substantially similar to the one
described above, but can alternatively produce any other suitable
plasma lamp.
Applying a first and second phosphor layer to a broad face of a
first and second lamp substrate S100 functions to apply the first
and second phosphor coating 400 over the interior surfaces of the
lamp substrates 200. The phosphor layers 400 are preferably
screen-printed (silkscreened, serigraphed, serigraph printed) onto
the broad faces of the lamp substrates 200, but the broad faces can
be otherwise coated with phosphor (e.g. sprayed, dipped, painted,
etc.). As shown in FIGS. 5A and 5B, the phosphor layers 400 are
preferably deposited as a blanket film over the broad faces of the
lamp substrates 200, wherein the phosphor layers 400 preferably
cover the majority of the broad faces of the lamp substrates 200,
except for the broad face perimeters. However, the phosphor layers
400 can alternatively cover the entire broad faces of the lamp
substrates 200 (e.g. wherein the frit seals along the edges of the
lamp substrate that are normal the broad faces), be patterned or
stenciled onto the broad faces such that the phosphor layer 400
only covers a portion of the respective broad face, or be deposited
in any suitable pattern. For example, three different screens can
be used in succession to print a checkered pattern of three
different phosphors (e.g. red, green, and blue). The phosphor layer
400 thicknesses are preferably substantially uniform, but can
alternatively be variable. The first phosphor layer 402, which
covers a broad face of the first lamp substrate 202, is preferably
substantially thin, more preferably a phosphor monolayer. The first
phosphor layer 402 is preferably less than 25 microns thick, more
preferably between 6-8 microns thick. However, the first phosphor
layer 402 can have any suitable thickness. The second phosphor
layer 404, covering a broad face of the second lamp substrate 204,
is preferably thicker than the first phosphor layer 402, wherein
the thickness is preferably selected depending on the given
application. The second phosphor layer 404 is preferably applied as
a single coating/layer, but can alternatively be formed from
multiple coatings/layers. Alternatively, the second phosphor layer
404 can be thicker, thinner, or the same thickness as the first
phosphor layer 402. The phosphor layers 400 are preferably made of
the different phosphor compositions, wherein the composition for
the first phosphor layer is preferably formulated to enable
phosphor monolayer screen-printing, and the composition for the
second phosphor layer is formulated to enable phosphor layer
screen-printing of the desired thickness. Alternatively, the first
and second phosphor layers 400 can have any suitable phosphor
composition. Applying a first and second phosphor layer 400 to a
broad face of a first and second lamp substrate 200 can
additionally include drying the phosphor layers 400. However,
applying the first and second phosphor layers 400 can alternatively
include dip-coating the lamp substrates 200 and removing excess
phosphor, depositing the phosphor layer 400 using particle
deposition, depositing the phosphor layer 400 with a phosphor spray
process, or any other suitable method of applying a phosphor layer
400 to a lamp substrate face.
Joining the first and second lamp substrates together S300
functions to form a substantially hermetic seal between the
perimeters of the first and second lamp substrates 200 and to
define the internal chamber 102 that contains a working gas. The
lamp substrates 200 are preferably joined together after phosphor
layer application. As shown in FIG. 6, joining the first and second
lamp substrates together preferably includes positioning spacers on
a broad face of a lamp substrate S320 and joining the lamp
substrates together using glass frit bonding (glass soldering, seal
glass bonding) S340.
Positioning the spacers S320 preferably defines the final
separation distance (gap distance) between the first and second
lamp substrates 200. The spacers 220 are preferably spherical
spacers with a diameter substantially equivalent to the desired
separation distance, but can alternatively be prismatic spacers 220
or have any other suitable geometry. The spacers 220 are preferably
positioned in an even distribution over the broad face of a lamp
substrate 200, such as in a grid pattern, but can alternatively be
only positioned along the perimeter of the broad face, positioned
in a random distribution, or positioned in any suitable manner.
Positioning spacers 220 on a broad face of a lamp substrate 200
preferably includes placing the spacers 220 in the desired
distribution onto a wet phosphor layer 400 that covers a broad face
of a lamp substrate 200, before the phosphor layer 400 has been
dried. The spacers 220 are preferably placed on one lamp substrate
200, but can alternatively be placed on both lamp substrates 200.
One variation of the method includes pressing the spacers 220 into
the wet phosphor layer 400 of the second lamp substrate 204 in the
desired distribution, then drying the second phosphor layer 404.
Alternatively, the spacers 220 can be included in the frit paste,
wherein application of the frit paste during glass frit bonding
simultaneously positions the spacers 220 on the broad face of a
lamp substrate 200. Alternatively, the spacers 220 can be
positioned on a phosphor-coated broad face after the phosphor layer
400 has been dried.
Joining the lamp substrates together using glass frit bonding S340
functions to form a substantially hermetic perimeter seal between
the two lamp substrates 200. Glass frit bonding preferably
includes: applying a bead of frit paste to the perimeter of a
phosphor-coated broad face S342; drying the frit paste; aligning
the first and second lamp substrates S344; applying a substantially
normal, compressive force against the broad faces of first and
second lamp substrates S346; and heating the assembly to flow the
frit. The frit paste is preferably applied to the phosphor-coated
broad faces of both the first and second lamp substrates 200, but
can alternatively be applied to only the phosphor-coated broad face
of the first lamp substrate 202 or only the phosphor-coated broad
face of the second lamp substrate 204. The frit paste preferably
traces substantially the entirety of the broad face perimeter,
wherein the frit bead is preferably substantially continuous, but
the frit paste can alternatively be applied as a plurality of beads
or strips. Frit paste application can additionally include
imbedding spacers 220 into the wet frit paste before drying. In one
variation of the method, the frit bead is approximately 2-3 mm
wide. Aligning the first and second lamp substrates 200 preferably
includes aligning the edges of the lamp substrates 200, wherein the
first and second lamp substrates 200 preferably have substantially
the same geometry. The lamp substrates 200 are preferably arranged
with the phosphor-coated faces proximal each other (e.g. on the
interior), but can alternatively be arranged with the
phosphor-coated faces on the exterior. The lamp substrates 200 can
be aligned by placing the first and second lamp substrates 200 in a
guide, or aligned in any suitable manner. The normal, compressive
force is preferably applied to the lamp substrates 200 after lamp
substrate alignment. The normal, compressive force is preferably
substantially evenly applied to the perimeter of the lamp
substrates 200, more preferably over the area including the frit
paste. Alternatively, the compressive force can be substantially
evenly distributed over the broad faces of the lamp substrates 200.
The compressive force is preferably applied by a plurality of clips
(e.g. evenly distributed about the assembly perimeter), but can
alternatively be applied by a pressure plate, by a pressurized
chamber, or any other suitable pressure application mechanism.
Heating the assembly to flow the frit preferably includes heating
the assembly (e.g. in an oven) above either the sintering or flow
temperature for the frit paste.
Applying electrodes to the exteriors of the first and second lamp
substrates S500 couples the electrodes 300 to the lamp exterior. As
shown in FIG. 7, a first electrode 300 is preferably coupled to the
uncoupled broad face of the first lamp substrate 202, and a second
electrode 300 is preferably coupled to the uncoupled broad face of
the second lamp substrate 204. The electrodes 300 are preferably
blanket films, but can alternatively be patterned. The electrodes
300 are preferably substantially the same size as the respective
uncoupled broad face, but can alternatively be larger or smaller.
The electrodes 300 preferably include transparent conductive films
of transparent conductive oxide (TCO), but can alternatively be
patterned metal such as copper, nickel, chrome, or any other
suitable electrode material. The electrodes 300 can additionally
include buss electrodes 340, wherein the buss electrodes 340 are
disposed between the electrode 300 and the lamp substrate 200 in
the final assembly. The buss electrodes 340 are preferably
conductive silver, but can alternatively be copper, gold, or any
other suitable conductive material. The buss electrode layer is
preferably 15-40 microns thick, but can alternatively be any
suitable thickness. The first and second electrodes 300 are
preferably substantially similar, but can alternatively be
different (e.g. different sized blanket films, different
patterning, different buss electrode 340 patterns, etc.). Each
electrode 300 is preferably supported by an electrode substrate
360, such as a glass plate, polymeric plate, polymeric film (e.g.
PET film), or any other suitable lamp substrate 200 for an
electrode 300. In one variation, the electrodes 300 include TCO
blanket films on glass plates. In another variation, the electrodes
300 include copper electrodes on PET film, patterned by
photolithography processes. However, any other suitable electrodes
300 can be used.
Electrode application to the lamp exterior S500 preferably includes
laminating the broad face of electrodes 300 to the uncoupled broad
faces of the first and/or second broad face of the lamp exterior.
The electrodes 300 are preferably laminated to the uncoupled broad
faces with adhesive, but can alternatively be laminated using any
other suitable lamination method. In one variation, UV-curable
adhesive, such as optical grade UV-curable epoxy, is used; however,
any other suitable epoxy or adherent can be used. In one variation
of the method, electrode application includes applying epoxy,
aligning the electrode 300 and the uncoupled broad face of the lamp
substrate 200, applying a compressive force on the electrode 300
against the broad face of the lamp substrate 200, and curing the
epoxy. The epoxy can be applied to the electrode 300, the uncoupled
broad face and/or the side of the electrode substrate 360 that
includes the electrode 300. The electrodes 300 are preferably
aligned by aligning the electrode substrates 360 with the uncoupled
broad face of the lamp substrate 200. Clips, guides, or any other
suitable alignment mechanism can be used. The alignment mechanisms
used in glass frit sealing the first and second lamp substrates
together are preferably used, but other alignment mechanisms can
alternatively be used. The electrodes 300 are preferably aligned
with the electrodes 300 proximal the uncoupled broad face of the
lamp substrate 200 and the electrode substrates 360 distal the
uncoupled broad face of the lamp substrate 200. Force is preferably
applied to the electrode 300 in a substantially normal direction,
but can alternatively be applied at an angle relative to normal.
Force is preferably applied to the face of the electrode substrate
360 opposing that supporting the electrode 300, but can
alternatively be applied to any suitable face. Force is preferably
applied by a pressure plate, but can alternatively be applied by a
roller or any other suitable force application mechanism. Curing
the epoxy preferably includes exposing the assembly to UV light,
but can alternatively include exposing the epoxy to oxygen or any
other suitable curing reagent or catalyst.
However, the electrodes 300 can be directly formed on the uncoupled
broad faces or joined to the uncoupled broad face of the lamp
substrates 200 in any suitable manner.
Applying the electrodes 300 to the uncoupled broad face can
additionally include forming the electrodes before electrode
application S520. The electrodes 300 are preferably formed from
electrode substrates 360 that have been pre-coated with conductive
material (e.g. TCO-coated glass substrates from a manufacturer),
wherein the conductive material functions as the discharge
electrode 320. In one variation, the electrode substrates 360 are
pre-coated with conductive material during the glass manufacturing
process. For example, a TCO film can be produced on the glass float
line at the same time that the glass electrode substrate 360 is
being made. However, the electrodes 300 can be formed from uncoated
electrode substrates 360, wherein forming the electrodes 300
further includes depositing conductive material on the electrode
substrates S522 to form discharge electrodes 320. Depositing
conductive material on the electrode substrates S522 can include
screen-printing a blanket film of conductive material on the
electrode substrate 360, screen-printing an electrode pattern onto
the electrode substrate 360 (e.g. using a pattern that prevents the
conductive material from being applied to the perimeter of the
electrode substrate 360), patterning electrodes 320 (e.g. copper
electrodes) onto the electrode substrate 360 using photolithography
techniques on blanket films produced using particle deposition,
metal organic chemical vapor deposition (MOCVD), metal organic
molecular beam deposition (MOMBD), spray pyrolysis, and pulsed
laser deposition (PLD), sputtering (e.g. magnetron sputtering) or
any other suitable electrode forming technique.
As shown in FIG. 8, forming the electrodes preferably additionally
includes forming a buss electrode over the conductive material
S530. Forming a buss electrode 340 preferably includes: removing
the conductive material from the perimeter of the electrode
substrate S532; depositing the buss electrode over the conductive
material/discharge electrode S534; and firing the buss electrode.
The conductive material of the discharge electrode 320 (e.g. TCO,
copper, etc.) is preferably removed from the perimeter of the
electrode substrate 360 to prevent creepage from the electrode 300
to the outside of the lighting tile. However, the conductive
material can be left on the perimeter. Removing conductive material
can include powder blast abrading, wet chemical etch (such as HF),
laser ablation, or any other suitable method. Buss electrode 340
deposition is preferably accomplished by screen-printing the buss
electrode 340 about the perimeter of the electrode 300. More
preferably, the buss electrode 340 is screen-printed onto the
discharge electrode 320 up to the edge of the remaining film after
film removal S532, such that a major portion of the buss electrode
340 covers the conductive material. However, the buss electrode 340
can be screen-printed such that the buss electrode covers both the
discharge electrode 320 and the electrode substrate 360.
Alternatively, the buss electrode 340 can be extruded, deposited
using particle deposition, or deposited in any other suitable
manner in any suitable pattern. The buss electrode 340 is
preferably silver, but can alternatively be gold, copper, or any
other suitable conductive material.
As shown in FIG. 8, forming the electrodes can additionally include
attaching electrical contacts to the buss electrode S536, which
functions to provide external contacts after the electrodes 300
have been laminated to the first and second lamp substrates 200.
These electrical contacts can additionally be electrically
connected to power connectors (e.g. soldering, crimping, etc.
wires, plugs, etc. to the electrical contacts) that enable
electrical connection to the terminals of a power supply. The
electrical contacts 342 preferably include tin-coated copper
ribbon, but can alternatively include any other suitable electrical
contact. Attaching electrical contacts 342 to the buss electrode
340 preferably includes soldering the electrical contacts to the
buss electrode 340, with a portion of the electrical contact 342
overhanging the electrode substrate 360. However, the electrical
contacts 342 can be screen-printed onto the buss electrode 340
(e.g. wherein a guide supports the overhanging portion of the
electrical contact) or coupled to the buss electrode 340 in any
suitable manner.
When the electrode substrate 360 is a film, applying the electrodes
300 to the first and second substrates can additionally include
coupling a protective substrate to the electrode S540, as shown in
FIG. 9. The protective substrate 380 can be coupled to the
electrode 300 after the electrode 300 is joined to the lamp
substrate 200, or can be coupled to the electrode 300 before the
electrode 300 is joined to the lamp substrate 200. When the
protective substrates 380 are coupled to the electrodes after
electrode application to the lamp substrates S500, both electrodes
300 are preferably first joined to the lamp substrates 200, after
which the protective substrates 380 are joined to the electrodes
300. However, the protective substrate 380 can alternatively be
coupled to the respective electrode 300 before joining the next
electrode to the lamp substrate. The protective substrate 380 is
preferably coupled to the electrode substrate 360, distal the
conductive material, but can alternatively be coupled to any
suitable portion of the electrode 300. The protective substrate 380
is preferably laminated to the electrode 300, but can be otherwise
coupled. The support structure is preferably laminated using an
adhesive, more preferably a UV-curable adhesive such as optical
grade UV-curable epoxy, but can be laminated using any other
suitable adhesive.
The method can additionally include providing the internal chamber
with a working gas S400. Providing the internal chamber with a
working gas preferably includes: providing an opening to the
internal chamber S420; evacuating the internal chamber S440,
filling the internal chamber with a working gas S460, and sealing
the opening S480. Providing the internal chamber 102 with a working
gas is preferably performed after phosphor layer application but
before electrode application.
Providing an opening into the internal chamber S420 functions to
allow fluid access to the internal chamber 102 after the perimeter
of the first and second lamp substrates 200 have been sealed
together. In one variation, as shown in FIG. 10, the opening 110 is
provided through the thickness of a lamp substrate 200. The opening
110 is preferably provided through the second lamp substrate 204,
but can alternatively be provided through the first lamp substrate
202. The opening 110 is preferably provided in a corner of the lamp
substrate 200, but can alternatively be provided through any
suitable portion of the lamp substrate 200. The opening 110 is
preferably formed during manufacture of the lamp substrate 200,
wherein the lamp substrate 200 is preferably molded or formed with
the opening 110. However, the opening no can be formed through
post-processing of the lamp substrate 200, and can be a hole that
is drilled, punched, or otherwise created through the thickness of
the lamp substrate 200. In this alternative, the lamp substrate 200
is preferably cleaned before and after hole formation (e.g. washed
with detergent). Hole formation preferably occurs before glass
strengthening, if glass strengthening is used. In another
variation, as shown in FIG. 11, the opening 110 is provided through
the frit seal, such that the opening 110 extends parallel to the
broad faces of the lamp substrates 200. In this variation, a tube
120 is preferably laid on the phosphor-coated face of a lamp
substrate 200 such that the tube end extends over the lamp
substrate edge, wherein the bead of frit paste is preferably
applied around a portion of the tube 120. The tube position is
preferably secured during frit paste drying. However, any other
suitable means of providing an opening no can be used.
Providing the opening can additionally include joining a tube to
the opening S430, which functions to provide a fluid path to the
internal chamber 102 after sealing the perimeters of the first and
second lamp substrates together. The tube 120 can additionally
function as an opening sealant. The tube 120 is preferably a
hollow, flared tube, but can alternatively be a hollow cylindrical
tube or have any suitable geometry. The tube 120 is preferably
glass, more preferably substantially the same glass as the lamp
substrate 200, but can alternatively be a polymer or any other
suitable material. In one variation, as shown in FIG. 6, joining a
tube with the opening S430 includes applying a bead of frit along
the edge of the tube, coupling the tube end with the frit to the
opening, and heating the frit to join the tube with the lamp
substrate. The bead of frit is preferably applied to the wide end
of the flared tube 120, but can alternatively be applied to the
narrow end of the flared tube 120. The tube end is preferably
substantially the same geometry as the opening 110, but can
alternatively be larger. The tube end is preferably coupled to the
exterior surface of the second lamp substrate 204, wherein the tube
120 is preferably coaxially aligned with the opening no. The tube
end is preferably coupled to the second lamp substrate 204 using
clamps or clips, but can alternatively be held in position by a
guide (e.g. the same guide that aligns the lamp substrates 200), or
positioned in any suitable manner. The tube 120 is preferably
joined and/or sealed against the lamp substrate 200 in the same
heating step that seals the first and second lamp substrate 200,
but can alternatively be joined before or after the first and
second lamp substrates 200 have been joined together.
As shown in FIG. 12, evacuating the internal chamber S440
preferably includes generating a low pressure within the internal
chamber 102 through the opening 110, wherein air and moisture is
pumped or pulled out of the internal chamber 102. Internal chamber
evacuation is preferably performed after joining the first and
second lamp substrates 200. Internal chamber evacuation is
preferably performed at a temperature higher than room temperature,
more preferably near the vaporization point of water, such that
moisture within the internal chamber 102 can be removed as water
vapor. Internal chamber evacuation is preferably performed with a
vacuum pump, or any other suitable low pressure generator. The low
pressure generator preferably attaches to the tube 120, but can
alternatively directly couple to the opening 110 (e.g. through a
suction seal).
As shown in FIG. 12, filling the internal chamber with a working
gas S460 preferably includes back-filling the working gas into the
internal chamber 102 after evacuating the internal chamber 102.
Internal chamber filling S460 is preferably performed at room
temperature after internal chamber evacuation S440, wherein the
assembly is preferably cooled before internal chamber filling. The
internal chamber is preferably filled with a noble gas mixture,
such as equal parts of neon and xenon. The internal chamber 102 is
preferably filled through the opening no. The working gas source
preferably couples to the tube 120, but can alternatively directly
couple to the opening no (e.g. through a seal).
Sealing the opening S480 preferably functions to hermetically seal
the working gas between the first and second lamp substrates 200,
and can additionally function to provide a substantially smooth
surface for electrode application. As shown in FIG. 13, the opening
no is preferably sealed by radially collapsing the free end of the
tube, which is preferably accomplished by localized heating of the
free end to melting temperatures. However, the opening 110 can be
sealed by flowing frit paste over the opening no, or by using any
other suitable method.
The method can additionally include processing the lamp substrates,
preferably after providing the opening 110 but alternatively
before. Substrate processing preferably includes strengthening the
substrate, but can include buffing the substrate, clarifying the
substrate, or any other suitable processing step. In one variation
of the method, processing the lamp substrate includes strengthening
a glass substrate by immersion in a potassium salt bath, such as a
potassium nitrate solution, with or without potassium silicate, at
elevated temperatures. This is preferably used when the lamp
substrate 200 includes soda-lime glass. In another variation of the
method, processing the lamp substrate includes both chemical
strengthening and glass lamination. However lamination, heat
treatment, or any other suitable method can
additionally/alternatively be used to strengthen the lamp
substrates.
One variation of the method includes: screen-printing a first and
second phosphor layer on a broad face of a first and second glass
plate, respectively; coupling the phosphor-coated faces of the
first and second glass plates together; screen-printing a first and
second electrode buss onto an electrode substrate; and coupling the
first and second electrode to the uncoupled broad faces of the
first and second electrode, respectively.
Another variation of the method includes: providing a first and
second glass plate; drilling a hole through the corner of the
second glass plate; cleaning the first and second glass plates;
strengthening the first and second glass plates by immersion in a
potassium nitrate salt bath; cleaning the first and second glass
plates; screen-printing a broad face of each of the first and
second glass plates with phosphor, wherein the broad face of the
first glass plate is coated with a phosphor monolayer, and the
broad face of the second glass plate is coated with a phosphor
layer having a thickness greater than the phosphor monolayer;
placing internal spacers into the phosphor layer coating the broad
face of the second glass plate; drying the phosphor monolayer and
the phosphor layer; applying a bead of frit about the perimeters of
the phosphor-coated broad faces; aligning and coupling the
phosphor-coated broad faces of the first and second glass plates;
applying a normal, compressive force to the uncoupled faces of the
glass plates; applying a bead of frit to a glass tube; coaxially
aligning the tube with the hole, with the frit proximal the
uncoupled face of the second glass plate; heating the assembly to
frit flow temperatures to seal the first and second glass plates
and to seal the tube to the second glass plate; evacuating the
interior chamber defined between the sealed first and second
substrates through the tube; backfilling the interior chamber with
a working gas through the tube; sealing the hole by locally heating
the free end of the tube, such that the tube collapses radially
inward; removing transparent conductive oxide (TCO) from the
perimeter of a first and second TCO-coated glass substrate;
screen-printing a first and second silver buss electrode about the
perimeter of the first and second TCO-coated glass substrates,
wherein the buss electrodes extend onto the TCO-coated portions of
the glass substrates; firing the buss electrodes; soldering leads
to solder pads on the buss electrodes; and laminating the first and
second TCO-coated substrates against the uncoupled broad faces of
the first and second glass plates, respectively, wherein the buss
electrodes and TCO layers are proximal the respective glass
plate.
Another variation of the method is substantially similar to that
described above, but uses PET films with copper electrodes instead
of TCO-coated glass substrates. In this variation, the method
includes the additional steps of laminating a first and second
piece of protective glass over the uncoupled broad faces of the
first and second PET films, respectively.
However, any suitable combination of the aforementioned actions in
any suitable order can be utilized to manufacture a lamp.
As a person skilled in the art will recognize from the previous
detailed description and from the figures and claims, modifications
and changes can be made to the preferred embodiments of the
invention without departing from the scope of this invention
defined in the following claims.
* * * * *